Arch-protector for boilers.



D. SMITH.

ARCH PROTECTOR FOR BOILERS.

APPLICATION FILED MAR. 25. 1916- mm ,,@@3., Patented July 3, 1917.

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DAVID SMITH, OF WELLESLEY, MASSACHUSETTS.

ARCH-PROTECTOR FOR BOILERS.

Specification of Letters Patent.

Patented July 3, lllil't.

Application fi1ed. March 25, 1916. Serial No. 86,769.

To all whom it may concern:

Be it known that 1, DAVID SMITH, a citizen of the United States, and a resident of Wellesley, county of Norfolk, State of Massachusetts, have invented an Improvement in Arch-Protectors for Boilers, of which the following description, in connection with the accompanying drawing, is a specification, like characters on the drawing representing like parts.

This invention relates to improvements in arch protectors for boilers and comprises a water cooled cylindrical conduit preferably extending through the thickness of the arch forming the mouth of the boiler and which is adapted to protect the brickwork of the arch from the destructive action of the heat of the furnace. It is also designed to reduce the temperature of the gases at the front of the furnace so that the fireman will not be injured thereby upon opening the furnace door to stroke the furnace.

All water cooled arch protectors which have been heretofore constructed have been made in substantially rectangular form to fit the usual mouths of the furnace which conform to the substantially rectangular doors of the furnace front, as a consequence such arch protectors have angular portions corresponding to the corners of the door and the expansion and contraction of the metal of such arch protectors often cracks the wall of the protector so that the water issuing from the crack is transformed into steam by the heated gases of the furnace and rushing from the furnace mouth as the door is opened scalds the fireman.

When such cracks occur it is difficult and practically impossible to repair the same so that the furnace arch has to be taken down and new arch preservers inserted.

The arch protectors heretofore made have either been'constructed of cast metal which is easily broken, or sections of pipe which are coupled together by usual joints or by built up structures in which the edges are riveted together by a number of distinct seams.

One of the objects of the present invention is to provide an arch protector in which there are no angles in its circumference and in which the strains of expansion and contraction will be uniformly distributed. This is accomplished by constructing an arch preserver of cylindrical form in which strains of expansion and contraction will be uniformly distributed and a structure of maximum strength provided.

Another feature of the invention consists in constructing the cylindrical arch preserver of two concentric cylindical sections the inner section havingits edges flanged upwardly and welded to the outer section by continuous seams so that the entire conduit comprises an integral construction in which the seams have the same properties of expansion and contraction as the body of the conduit so that there is no tendency to break during the expansion and contraction.

Other features of the invention will more fully appear from the following description and accompanying drawings and will be pointed out in the annexed claims. The drawings illustrate a portion of a steam boiler furnace embodying my invention showing the'novel form of arch protectors and the means connecting the same to the boiler to form a water circulating system through the arch protectors.

In the drawings;

Figure 1 illustrates the front of the furnace partly broken away to show one of the arch protectors and its connections to the water circulating system.

Fig. 2 is a plan View partly in section of the arch protectors embodied in the furnace wall the protecting plate in one of the arch protectors being broken away to disclose the refractory filling at the bottom of the arch protector.

, The a furnace illustrated in the drawing comprises a usual fire brick structure 1 forming the front of the furnace which supports the end of the boiler 2, the brick of the front wall usually being stepped back to underlie the end of the boiler beyond .the series of rivets connecting the boiler head to the cylindrical body portion thereof. The wall 1 as illustrated herein is provided with circular months in which are fitted cylindrical arch protectors. These arch protectors preferably are constructed of a cylindrical metallic outer shell or wall 3 of sufiicientlength to extend through or sub joined together at both edges by weldedv scams 6 so that the conduit is in effect an integral structure. By reason of its cylindrical form this arch preserver has the maximum strength to resist compression strains and also is adapted to expand uniformly throughout so that there is no danger of cracking as would be the case if the arch preserver embodied angular portions. The inner and outer walls being of the same material and welded together are adapted to expand uniformly so that the danger of breakage at the seams is eliminated.

Circulation of water from the boiler through the arch protectors is maintained through a series of pipes 7, 8 and 9 which are screw threaded into plates 10, 11 and 12 welded to the outer shell around apertures in said walls.

The pipe 7, which is connected by the inlet pipe Ll with the boiler, preferably communicates with one of the arch preservers in substantially the horizontal plane of its axis and a pipe 9 preferably leads from the arch preserver to its companion arch preserver in the same horizontal plane. For convenience in assembling the pipe 9 is made in two sections connected by a suitable union 15. The outlet pipes 8 preferably are located at the top of each of the arch protectors and are connected to a common return pipe 16 leading to the boiler. By this construction a more rapid circulation is provided in the upper part of the arch preserver which is subjected to the greatest amount of heat.

In order to provide for the removal of sediment from the arch preserver additional pipes 17 may be provided at the bottom of the arch preserver leading to blow-off valves 18. In the construction of the furnace the arch protectors may be supported conveniently upon tubular transverse struts 19, 20 supported at their ends upon suitable piers and embodied in the brickwork of the furnace wall.

In this construction the lower portion of the arch extends beneath the level of the grate bars of the furnace which are substantially open and level with the lower edge 21 of the furnace doors 22. The lower portions of the arch protectors are filled with a refractory material 23 such as fire brick and this is covered by a plate 24 which willprotect it from injury by the furnace tools.

Arch protectors of this character may be constructed at a relatively low cost and their immunity against breakage fromexpansion and contraction due to the changing temperatures in the furnace mouths enables them to last for a much longer period than arch protectors heretofore made. The manner of their connection in the fluid system is such as to cause the sediment to settle at the bottom so that it can be removed by opening the valves of the blow-off pipes and incrustation thereby be largely prevented.

t is to be understood that the particular constructiondisclosed herein is illustrative and that modifications in form may be made within the meaning and scope of the following claims, for example, the term cylindrical is to cover all structures in which the walls are of a continuously curved construction avoiding angular parts. 7

It is also to be understood that the claims are intended to coverconstructions in which the inner and outer cylindrical walls may be formed integral either atone end or both and that my invention is subject to the usual modifications of form, size, and material.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

1. An arch preserver for a furnace mouth comprising a metallic conduit having a cylindrical outer wall and an inner concentric cylindrical wall having its ends flanged outwardly to engage the outer wall, the inner and outer walls being secured together by continuous welded seams to form an in tegral structure and inlet and outlet means adapted to provide connections-to a fluid circulating system.

2. An arch preserver for a furnace mouth comprising a metallic conduit having a cylindrical outer wall of sufiicient length to extend wholly or substantially through the thickness of the furnace wall and an inner concentric wall having its end portions provided with outwardly curved flanges to engage the outer wall, the inner and outer walls being secured together by continuous welded seams to form an integral structure and inlet and outlet means adapted to provide connections to a fluid circulating system.

3. An arch preserver for a furnace mouth comprising a metallic conduit having a cylindrical outer wall and an inner concentric cylindrical wall, one of said walls having its ends flanged to engage the other wall, the outer and inner walls beingsecured together by continuous welded seams to form an integral structure and inlet and outlet means adapted to provide connections to a fluid circulating system.

4. In a furnace for steam boilers a front wall having a cylindrical mouth, an arch protector in said mouth comprising an integral cylindrical metallic conduit extending substantially throughout the thickness of said furnace wall, the lower portion of the interior aperture of said arch protector being filled with a refractory material, a cover plate protecting said infrangible material, means connecting said conduit with the boiler to provide for the circulation of the water through said conduit and a furnace front provided with a metallic door covering the open ends of the aperture through said arch protector.

In testimony whereof, I have signed my name to this specification.

DAVID SMITH.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C. 

